it's not your son's short and small umbilical cord. Kawamata Nao

Nao has been dissatisfied with sex with her husband for several years after she got married. One day, a mother of the Yamada family who lives next door encounters a scene in which her son Yoshiyuki is being scolded. His mother, whose son had been bought a futon by visiting sales and her anger did not subside, told Yoshiyuki 'short-lived son!' and slashed it with cruel words. After that, he accidentally witnessed Yoshiyuki masturbating. The meat stick that was smeared by her mother as "short-sized" is a wonderful thing, and Nao unexpectedly went up to Yoshiyuki's room.